Adjust color balance/brightness/contrast on scanned mesh
The file used in this question is of Stanford PLY format, vertex colors, no textures.

When the mesh is selected, changes in brightness etc. that applies to the whole mesh is found under:

"Vertex Paint" - "Paint" - "brightness/contrast"-"Hue Saturation level", "Levels" "and "Invert"

The screenshot below demonstrates the solution using the "brightness/contrast" parameters